I mean, imagine if a good natured mad scientist see their prejudice against robots, and kidnaps the cousins to teach them a lesson?
Get them at night and take them to his hideout, there he put them to sleep and chop off their limbs, exchange their eyes for some cool led cameras, and some treatment on their skin to make it always shiny and pure, replacing them for some other enhanciments. Finishing the process by implanting some probes on their brain to make sure that he can control their behavior and emotions.
So when they wake up they have all that shock that they became that thing that they always hated, but can not really do anything against the scientist because it is agaisnt their new protocol.
The scientist make them go trhouth every kind of thing humiliating them, like making them clear his office lewdly, help him in his scientiphic reasearch or sucking him off. He makes sure to only allow them to talk appropriate things. When night comes he just put them on a box on the wall to recharge, and they are aware every time and cant sleep or say anything. They start angry but break after some days.
Seeing them unhappy makes the scientist bro show them some stimatives on how their future would have been if they never were kidnapped, he shows them that on most likely scenarious they would have ended up like sad fat husks of their former selves - like the show EVEN showed on a flashfoward, so it is pretty much canon.
This forces them to reavaluate the situation and try to make execuses out of their existence, if they are to be sad in the future anyway, the least they can do this looking pretty for ever as this guy sexbots.